Sinead Sweeney (18) from Castlewellan served Ellen a meal on Friday evening at the Percy French restaurant in Newcastle where they both worked part-time.

But at around 4am on Saturday morning, a fire broke out in the bedroom above Ms Finnegan's father's butcher's shop in Lower Square, Castlewellan. Despite the strenuous efforts of fire officers and paramedics, the teenager could not be saved from the blaze.

"Ellen was a great girl, one of a kind, we practically grew up together," Ms Sweeney told the Belfast Telegraph yesterday.

"I'm so glad she came in now, as I was not meant to be working that night. Ellen was sitting there in the corner with a friend and I was keeping her going and joking, 'You take it easy, with me serving you', but now, I would do anything to be able to do it again for her."

"She said her daddy, Bartley, was going skiing the next morning and she was going home to help him pack. She talked about coming to see me and my friend at my flat in Belfast on Monday night. She was just herself, as lively as normal. When the news came out on Saturday morning, I just couldn't believe it."

The two young women had known each over since they were young children, attending St Malachy's Primary School in Castlewellan before going to Assumption Grammar in Ballynahinch.

Ellen was an A-Level student at Assumption Grammar and had just received three university offers for next September.

She had opted to repeat Year 13 in order to give herself the best chance for a university place and was hoping to do a business degree in Liverpool.

An only child, Ellen's young life was marred by the early death of her mother Nicola, who died after a three-year battle with bowel cancer at the age of 49 on January 16, 2013.

Ellen - said by friends to be her mother's double in looks and spirit - coped admirably with her loss when she was doing her GCSEs. Mrs Finnegan was a popular local businesswoman who established a youth training programme with Hugh J O'Boyle Training Ltd in Downpatrick.

The Finnegan family are a respected and popular family in the south Down area and the tragic death of Ellen, so soon after her mother, has hit the community hard.

People placed floral tributes on a bench seat in front of Finnegan's Butchers yesterday as the close-knit community of Castlewellan mourned the loss of such a young life.

Dozens of bunches of flowers had been laid on and around the bench, with heartfelt messages of grief and one girl leaving a photograph of her and Ellen together when they were just children.

But for local people trying to make sense out of the tragedy, one young man's reaction to the tragedy summed it up as he simply left his bouquet and walked away, shaking his head in disbelief. Ms Sweeney added: "Ever since I've known Ellen, she was very close to her mother and father and she was their world.

"It was always just the three of them. Ellen's mummy pushed her to be the best at everything and she was.

"She was a great skier, netball player, camogie, horse-rider, she would have tried anything."

"Ellen was easily one of the brightest girls in the school.

"She wanted to get the top grades and she would have deserved it as she was doing so well at school this year."

Ms Sweeney was one of more than 200 pupils, past pupils and teachers who attended a special prayer service at Assumption Grammar yesterday afternoon.

Some of those who attended were Ellen's friends and class mates and had travelled back to their old school from their universities in England and Dublin to pay their respects.

Mrs Marcelle Orsi, Assumption's head of senior school, said: "With Ellen, we have lost one of our dearest. She could light up any classroom she walked into.

"She was just such a warm and bubbly character and was very popular with both students and staff, and junior school, and of course, the senior school.

"Because she repeated year 13, she straddled two year groups and was able to have friends in both years.

"Ellen just had one of those personalities that drew people to her.

"She had huge big eyes and a big smile and was just a beautiful young girl with so much potential.

"Her GSCE teacher, Mrs Lewis, who has just retired, is terribly upset about Ellen's death as she worked very closely with Ellen after her mother died as it came right in the middle of her GCSE year."

Mrs Orsi (left) added that the death was "absolutely heartbreaking" for Ellen's distraught father Bartley, who she and the principal Peter Dobbin had visited the day before.

It is understood that Ms Finnegan's funeral will take place at St Malachy's Church, Castlewellan on Wednesday.